Please observe the tetrad of duplicated homologous chromosomes. Have a single crossover take place  involving only two of the four chromatids between the B/b alleles and the D/d alleles. The crossover must take place between non sister chromatids. What combinations of alleles are now present on the chromatids?

What processes are responsible for the generation of genetic variation during meiosis, and at what point in meiosis does each occur? Random alignment and separation of homologs that takes place during metaphase I and anaphase I, respectively. Independent assortment of homologous that takes place during anaphase II. Crossing over of non-sister chromatids that take place during prophase I. Replication of DNA during the S phase.

Answer below is wrong:

why two crossovers are needed on one chromatid arm? explain please

The phenomenon of crossing over, which occurs in Prophase I, causes:     the same allelic combinations as before.     the exchange of segments between nonsister chromatids.     the separation of homologous pairs.     the duplication of tetrads.

Considering both asexual and sexual reproduction, does the following statement apply to mitosis only, meiosis only, or both mitosis and meiosis? Mutations that occur during this process would ALWAYS be passed on to the next generation     Neither mitosis nor meiosis     Both mitosis and meiosis     Meiosis only     Mitosis only

A schematic drawing of a Holliday junction is shown next. One chromatid is shown in red, and the homologous chromatid is shown in blue. The red chromatid carries a dominant allele labeled A and a recessive allele labeled b, whereas the blue chromatid carries a recessive allele labeled a and a dominant allele labeled B.

In fruit flies, chromosomal crossing over does not occur in meiosis in males, whereas crossing over does occur in meiosis in females. In fruit flies that are heterozygous at many genes (i.e. many maternal and paternal versions of the genes differ), at what stage would cells no longer be heterozygous for any gene during the process of meiosis? a)After the second meiotic division in males, and after the first meiotic division in females. b)After the second meiotic division in both males and females. c)After the first meiotic division in both males and females. d)After the first meiotic division in males, and after the second meiotic division in females.

Based on the attached image, identify the stage at which each cell is in and draw an animal cell with a diploid chromosome number of 6. Indicate maternally- & paternally-derived chromosomes as red and blue, respectively, in your diagram. You do not need to indicate any crossing over. Be sure to include any of the indicated labels.

In Figure 17-28, what would be the consequence of acrossover between the centromere and locus A?